More On M.2 And SanDisk's Fancy PCIe Adapter Card

In case the previous page didn't clarify M.2 for you, don't sweat it. I created the diagram above to (hopefully) inject some clarity, since this entire discussion gets a little confusing. In reality, M.2 refers to the connector manufactured by companies like Kyocera and Tyco. Again, solid-state drives employing the M.2 connector are 22 mm wide, better accommodating NAND packages and processors down the length of the PCB. That length can be 42, 60, 80, and 110 mm. So, a M.2 2260 is 22 mm wide and 60 mm long. Get it?

That's the obvious, physical stuff. There's also plenty to digest when it comes to the technology on an M.2-based SSD. Use a SATA controller, and you end up with something similar to an mSATA-equipped drive (so long as the M.2 slot is wired up to a corresponding SATA port on your motherboard; otherwise, there needs to be a PCIe-to-SATA bridge chip in play).

Then you have native PCI Express controllers like the one on SanDisk's A110. It boasts Marvell's 9183, which, communicates across those two lanes of second-gen PCI Express. There will be native NVMe-based controllers that attach via PCIe and work with the upcoming host interface. For now, though, the A110 is limited to AHCI. This is the case for every current and most upcoming M.2 PCIe-based drives.

Still following along? Let's pile on some more. SSDs with M.2 connectors can use one, two, or as many as four PCI Express lanes. SanDisk's sample employs two PCIe 2.0 lanes, which should become fairly standard, we understand.

We probably don't need to tell you that the test platforms already in our lab don't yet support M.2. One motherboard vendor is starting to show off LGA 1150-based platforms with M.2 linked to one PCIe lane, but we'd prefer to use our main SSD testing setup. Not only would stepping over to a new board yield different results, but limiting the A110 to one lane would inhibit its performance.

That's why we need this bad boy:

This is SanDisk's PCIe x4 to M.2 adapter. Without a proper slot to accommodate the A110, we need this full-height card to test any SSD with an M.2 connector. These are for testing and development, and come with a variety of arcane jumpers, along with a USB port for debugging. The PCIe-based M.2 can be powered through either the PCIe bus or the four pin Molex. That'll come in handy for power consumption testing.

With just two different PCIe M.2 form factors, the adapter doesn't need to support every length. Installing the M.2-based SSD is easy; plug it in the connector and then secure it with a cylindrical barrel.

It will be nice to see vendors implement the NVMe connectors in the desktop mobo's, which in turn will redefine case design, as less storage space will be required for storage. I am aware that the initial intent is to direct these at the mobile market, but desktops can benefit as well.

It will be nice to see vendors implement the NVMe connectors in the desktop mobo's, which in turn will redefine case design, as less storage space will be required for storage. I am aware that the initial intent is to direct these at the mobile market, but desktops can benefit as well.

You'll really see NVMe take off on the desktop with the move towards SATA Express. A SSD on SATA Express will leverage NVMe and two PCIe Gen 3 lanes. Though some motherboards will (and already do) have M.2 connectors, M.2 really makes more sense in mobile applications. M.2 will only get traction on the desktop insofar as it will begin to replace mSATA. Tons of mainboards, especially smaller form factor products embrace mSATA, and moving to M.2 is a natural transition. However, M.2 drives are hard to find right now, and we really won't see a plethora of options until next year.

I may no longer have motivation to upgrade my system based on CPU specs, but with DDR4, M.2, new restive storage based SSDs, and better chipset features I will still have enough reason to upgrade in a year or two.

It will be nice to see vendors implement the NVMe connectors in the desktop mobo's, which in turn will redefine case design, as less storage space will be required for storage. I am aware that the initial intent is to direct these at the mobile market, but desktops can benefit as well.

You'll really see NVMe take off on the desktop with the move towards SATA Express. A SSD on SATA Express will leverage NVMe and two PCIe Gen 3 lanes. Though some motherboards will (and already do) have M.2 connectors, M.2 really makes more sense in mobile applications. M.2 will only get traction on the desktop insofar as it will begin to replace mSATA. Tons of mainboards, especially smaller form factor products embrace mSATA, and moving to M.2 is a natural transition. However, M.2 drives are hard to find right now, and we really won't see a plethora of options until next year.

Regards,Christopher Ryan

That's what I was thinking. SATA Express is going to be fast enough for now as I have used PCIe SSDs before (OCZ Revo based drive) and compared to my 520 its hard to notice a difference, especially since there are other bottlenecks stopping it from being able to utilize that bandwidth.

the power numbers don't make a lot of sense. I suspect either the pcie interface is being kept in a high-power mode (plls running, etc) or else your molex is supplying power to other stuff on the board. (there must be a dc-dc regulator on the auxiliary card, since molex provides only 12,5.)

the power numbers don't make a lot of sense. I suspect either the pcie interface is being kept in a high-power mode (plls running, etc) or else your molex is supplying power to other stuff on the board. (there must be a dc-dc regulator on the auxiliary card, since molex provides only 12,5.)

This is almost certainly true. I mean, we know it uses DC to DC to step the 5v down to 3.3v. But oddly, SanDisk rates the max write power consumption at 5.5w, and I could only get it max at 3.5w. Of course, it also possesses a deep slumber state, but that's contingent on having a L1.0 PCIe endpoint, and that hasn't even been ratified yet by PCI-SIG.

So definitely take the power consumption results with a grain of salt. There are challenges to testing this drive in this way.

will there be RAID or SLI/CFX for PCIe based SSD's?I don't think so b/c it's already way above 6G limit.

If you happened to have the ability to run two+ PCIe SSDs, M.2 or otherwise, you can always soft-raid them. There are reasons why you'd want to avoid such a setup, but it'd totally work. Intel's 910 PCIe SSD shows 2 or 4 drives to the OS and then they can be soft-raided from there, for instance.

It seems like new progress is being made in the field of NAND every day. I can't wait until you can get high capacity drives for around the same price as HDDs, but I've heard that even as late as 2017 SSD storage will only have a 33% share.

I'm a complete novice to all this stuff, yet I have a few questions that maybe someone can answer.

Are these M2 devices still considered SATA drives?Using a PCIe (or other) interface for the M2 how could you clone these devices?Can these devices then be cloned using a standard HDD duplicator?Is there such a thing as a M2 "adapter" that plugs into the above duplicator?

On page four of this review, in the maximum 4kb speed chart, it says "in MB/s [higher is better]." However, shouldn't that refer to the fact that it is measuring max IOps, rather than write speed? It seems like a type to me, so I wanted to let you know.